Conventionally, in order to control the persons getting in and out of an office building, a magnetic-attraction door lock is generally installed on a door for the persons in and out. Also a sensor is provided outside the door, while a button switch (normally on) is provided inside the door. The button switch stays in a normal condition and is electrically looped with the magnetic-attraction door lock. When the button switch is pushed, the circuit is instantly at a power-off state; when a person enters, the magnetic-attraction door lock is disabled by means of magnetic card induction so that the magnetic-attraction door lock stays at a disable state to open the door. When the person is going out, s/he pushes the button switch to instantly power off and disable the magnetic-attraction door lock, thereby the magnetic-attraction door lock staying at a disable state. With an oil pressure device, the door automatically opens for the person to go out.
Although the button switch may be used to power off the magnetic-attraction door lock, the magnetic-attraction door lock may be disabled to stay at a disable state, which thus make the door open for the person to go out. However, after the person goes out, the door is automatically close because being provided with the oil-pressure shut device.
Thus, for the conventional button switch, when more persons pass in and out of the building through the door, for example, at the time of on duty and off duty, because the button of the switch cannot be firmly fixed, an electrical conduction part and an electrically conductive pad stays at the power-off state for long time. Thus, a person is requested to push the button of switch, in order for the power-off state to not make the electrical conduction part contact the electrically conductive pad, or alternatively an iron chain or a rope is used to fix the opened door, which, as a result, is inconvenient to a user. Accordingly, the conventional button-based normally closed (on) switch is impractical and does not satisfy the user.